How would you like to receive a diagnosis of chronic mental illness, be placed on leave from your job, and be tormented by depression, insomnia, anxiety, and obsessive thoughts—when your real problem was too much tuna fish? It happened to a young teacher in Alberta, Canada.

A published report on this man in the Journal of Forensic Science demonstrates the role toxic exposures can play in mental health. The teacher was suicidal by the time he reached Dr. Stephen Genuis, MD. A member of the American Academy of Environmental Medicine, the doctor ran tests that revealed high levels of mercury. It was learned that the teacher had eaten canned tuna every day for years. After changing his diet and undergoing treatment to reduce mercury levels, the patient started to improve. Within eight months, he was symptom-free, discontinued his medications, and returned to work.

Genuis notes that a range of environmental toxins can affect brain function, emotion, thinking, and behavior. He suggests that chemical toxicants should always be considered when a patient is demonstrating neuropsychiatric symptoms.